docs: def get(self, word, default=nil):
  		"""
  		Retrieves output value associated with word.
  
  		If there is no word returns default value,
  		and if default is not given rises KeyError.
  		"""
  
  		node = self.__get_node(word)
  		output = nil
  		if node:
  			output = node.output
  
  		if output is nil:
  			if default is nil:
  				raise KeyError("no key '%s'" % word)
  			else:
  				return default
  		else:
  			return output